Bifold doors in Milan villa unite house and garden.

Layered design in the boundary between interior and exterior living spaces.

This design show-cases Lacuna doors. So just what are bifold doors? Think zig zag! Or musical squeeze box. Each door hinges on both edges. And they hang from a rail. So they slide and open at the same time. This is why they can fill wide openings.

But isn’t there a groove collecting dirt in bifold doors?

Not on these. Because the Lacuna system does not need a floor groove. So bifold doors are a moving wall. Across a simple clean threshold. A wall you can see through. And one  that disappears. When open three doors stack on one side of the opening. Stacking on edge means less profile.

Lacuna’s Morten Wendt says… “in bifolding doors…

… the main rule is that you always need an odd number to one side, as a W shaped 4 leaf door will not be tight…”

What an opening! Space flows between in and out. Therefore bifold doors are a step change. A revolution in how a house relates to its garden. This client wants a layered design of the garden-house boundary.

French windows are SO last century!

French windows are the traditional way from inside to outside.  A pair of wood and glass doors opens out. They hinge on a frame. So their weight limits their width. To not much more than 600mm. Or two feet.  A single bifold door can be 1200mm wide. That’s four feet! In large openings there may be two pairs of French windows. Or one pair with fixed side windows.  But this means lots of wood. A big bifold door means more glass than frame.

Bifold doors? No parking!

Then come sliding doors. Metal frames and toughened glass allow bigger doors.  But they have to park.  Therefore only half the opening is ever open.  Even then you see a clutter of frames at the overlap. And the sliding parts can often fail. Runners collect dirt. Which obstructs smoothness. But yes they’re bigger. But I designed pocket Skyframe doors here. That project avoids the parking problem.

Clever gear in bifold doors.

Finally door gear got clever. Gear means the rail, hangers, guides and hinges. Lacuna make them with stainless steel. Here is their technical summary. That’s marine grade, the toughest. But with nylon for smoothness. Each piece is made so precisely. To much finer size than before. Computer guided cutters are the secret. These clever machines can make tiny parts. Which are cut to fine accuracy. So parts fit together tight. Altogether the result is bifold doors fitting securely.

These bifold doors are very strong. As well as good looking. Lacuna , a Danish company, heat treats the wood. Consequently it’s hardened.  Therefore resistant to changes from moisture.